Ubiquitous expression of marker transgenes in mice and rats

The ability to unambiguously mark a cell's genotype is essential for studie s in which genetically distinct cell populations must be distinguished from one another in vivo. One approach to this challenge has been the creation of transgenic mice expressing a transgene marker that is easily detectable, with no background staining. Multiple transgenic mouse strains bearing con structs with different combinations of promoter elements and coding sequenc es have been described, each with its own advantages and limitations. In th is report we describe the use of an 800-bp promoter fragment isolated from the beta geo integration site in ROSA26 mice to target expression of two ma rker genes. We demonstrate that the ROSA26 promoter directs ubiquitous expr ession of human placental alkaline phosphatase and enhanced green fluoresce nt protein during embryonic and postnatal development in mouse and rat. We further demonstrate the general utility of these transgenes for marking don or cells in transplantation studies. (C) 1999 Academic Press.